The first robbery happened shortly after 2 a.m. at the 7-Eleven on King Street, just past the Hotel Northampton. It was followed by a holdup about 20 minutes later at the Cumberland Farms store on Main Street in the Florence section of the city.

A state trooper detained a suspect, 26-year-old Marcus Roberson, on Bridge Road at about 3 a.m., Sgt. Adam Hakkarainen said.

Trooper Timothy Harrington then turned the suspect over to city police who made the formal arrest, said Hakkarainen, who is attached to the Northampton barracks.

Hakkarainen said Roberson, who turned 26 yesterday, is a suspect in at least one of the armed robberies. Hakkarainen referred further comment on the arrest and the investigation to city police, who were not immediately available for comment.

The charges filed against Roberson were also not available.

This is a developing story that will be updated as our reporting continues.